Nonstalling gasoline motor fuel



United States Patent Office 3,033,665 Patented May 8, 1962' Delaware NoDrawing. Filed Aug. 1, 1958, Ser. No. 752,411 9 Claims. (Cl. 4466) Thisinvention relates to gasoline fuel compositions, and more particularlyto gasoline fuel compositions that have reduced engine stallingtendencies at cool, humid atmospheric conditions.

When an internal combustion engine is operated at cool, humidatmospheric conditions, using a gasoline fuel having a relatively low 50percent ASTM distillation point, i.e., below about 235 F., excessiveengine stalling is apt to be encountered at idling speeds during theWarm-up period, especially where engine idling occurs following a periodof light load operation. Engine stalling under such conditions has beenattributed to the partial or complete blocking of the narrow air passagethat exists between the carburetor throat and the carburetor throttlevalve during engine idling, by ice particles and/or solid hydrocarbonhydrates that deposit upon and adhere to the metal surfaces of thecarburetor parts. :Such icing of carburetor parts occurs as a result ofthe condensation of moisture from the air drawn into the carburetor andas a result of the solidification of such condensed moisture. Theaforesaid condensation and solidification of moisture are caused by therefrigerating effect of rapidly evaporating gasoline. Accordingly,excessive engine stalling due to carburetor icing occurs as a practicalmatter only in the instance of gasolines containing a large proportionof relatively highly volatile components. In practice, the problem ofengine stalling due to carburetor icing has been found to be serious,under cool, humid atmospheric conditions, in connection with gasolineshaving a 50 percent ASTM distillation point below about 220 F.

Excessive engine stalling is, of course, a source of annoyance owing tothe resulting increased fuel consumption, battery wear and inconvenienceof frequent restarting. It is therefore important that the inherentengine stalling characteristics of gasoline fuels be reducedsubstantially where the 50 percent ASTM distillation point of suchgasoline fuels is sufficiently low to cause a problem in this respect.

The present invention relates to gasoline fuel compositions thatcomprise hydrocarbon mixtures boiling in the gasoline range and thatnormally tend to promote engine stalling by carburetor icing, which fuelcompositions exhibit reduced engine stalling tendencies, and which arethereby rendered more suitable for use as motor fuels. We have foundthat such improved gasoline compositions can be obtained byincorporating therein a small amount of a quaternary ammonium saltwherein two of the covalent N-bonds are attached to aliphatichydrocarbon substituents containing 8 to 22 carbon atoms and theremaining covalent N-bonds are attached to saturated aliphatichydrocarbon radicals containing 1 to 4 carbon atoms, and wherein theionic N-bond is attached to an anionic salt-forming radical derived froma member selected from the group consisting of (a) oil-soluble organic Imono-carboxylic acids containing 7 to 30 carbon atoms per molecule, (b)oil-soluble monohydric phenols having attached to the aromatic nucleus 1to 3 hydrocarbon substituents containing at least four carbon atoms, andhaving not more than one substituent in the ortho position that containsmore than one carbon atom, (c) oil-solube monoand di-acid esters ofo-phosphori'c acid having as one phosphato substituent an aliphatichydrocarbon radical containing 8 to 22 carbon atoms, and as another amember selected from the class consisting of hydrogen and aliphatichydrocarbon radicals containing 2 to 22 carbon atoms, and (d)oil-soluble hydrocarbon sulfonic acids. Especially good results areobtained from di-C alkyl, di-C alkylammonium dialkyl o-pho'sphates andalkyl phenates, such as dioctadecyldimethylammonium di Oxo octylo-phosphate, bis(dioctadecyldimethylammonium isooctyl o-phosphate,dioctadecyldimethylammonium p-tert-octyl phenate. However, good resultsare also obtained with other quaternary ammonium salts of the classdisclosed, for example, dioctyldecyldimethylammonium naphthenate,dioctadecyldimethylammonium oil-soluble petroleum sulfonate, and others.The invention is important in connection with gasolines having a 50percent ASTM distillation point not greater than about 220 F., as suchgasolines normally involve a severe engine stalling problem due tocarburetor icing.

I The quaternary ammonium salts Whose use is included by this inventionare polar, surface active materials. While the invention is not limitedto any theory of operation, it might appear that the addition agentsdisclosed herein, by virtue of their polarity, tend to orient themselvesupon the metal surfaces of the throttle valve and other criticalcarburetor parts contacted by the gasoline compositions, thus forming amoisture displacing residual coating upon said carburetor parts whichtends to prevent theadherence to said metal surfaces of accumulations ofice of such magnitude as to block the narrow air passages that exist ina carburetor throat at engine idling conditions. It is also consideredpossible that the addition agents disclosed herein may tend to orientthemselves about small, ice particles, thus tending to prevent theformation of macrocrystals of ice of a size suflicient to blockcarburetor air passages at engine idling conditions. Although theelfectiveness of the herein disclosed addition agents is believed to beattributable in some way to the particular polar, surface activecharacteristics thereof, this general explanation is more or lessnegatived by the fact that many other surface active agents, includingfor example, other quaternary ammonium salts, have little or no effectupon the carburetor icing tendencies of gasolines.

The quaternary ammonium salts disclosed herein can be prepared in anysuitable manner. Inasmuch as'the method of preparing the quaternaryammonium salts disclosed herein does not as such constitute any part ofthis invention, such preparation need not be described in detail.However, in the interest of clarity it may be mentioned that accordingto a preferred procedure the quaternary ammonium salts disclosed hereinare formed by neutralizing an appropriate quaternary ammonium hydroxidewith an oil-soluble acid of the kind disclosed herein. This reactionproceeds spontaneously at ambient atmospheric conditions with evolutionof heat. The quaternary ammonium hydroxide is conveniently prepared byreacting a suitable quaternary ammonium halide with an alkali metalhydroxide, e.g., potassium hydroxide'in an alcoholic solution, thusforming a precipitate of an alkali metal halide and an alcoholicsolution of a quaternary ammonium hydroxide. Several quaternary ammoniumhalides suitable for use in preparing the quaternary ammonium saltsdisclosed herein can be obtained commercially. When this is not thecase, the desired quaternary ammonium halide can be prepared inconventional fashion, i.e., by reacting an appropriate tertiary aminewith an appropriate alkyl halide. The detailed preparations of severalquaternary ammonium salts of the kind disclosed 3 herein are describedin the present assignees copending application Ser. No. 538,799, filedin the name of Earl E. Myers, on October 5, 1955.

Any quaternary ammonium hydroxide having two of its covalent N-bondsattached to aliphatic hydrocarbon substituents containing 8 to 22 carbonatoms and the remaining covalent N-bonds attached to aliphatichydrocarbon atoms containing 1 to 4 carbon atoms can be utilized to formquaternary ammonium salts useful for the purposes of this invention. Itis important that two of the covalent N-bonds be attached to long-chainaliphatic hydrocarbon substituents as the presence of two suchsubstituents imparts especially desirable gasoline solubility and waterinsolubility characteristics to the quaternary ammonium salts. Suchcharacteristics are important to avoid any reduction in antistallingproperties on account of a reduction in the effective concentration ofthe addition agent due to separation from solution or water leaching.The long-chain aliphatic hydrocarbon radicals can be, for example,alkyl, alkenyl or alkadienyl radicals containing 8 to 22 carbon atoms.Quaternary ammonium hydroxides wherein the two long-chain aliphatichydrocarbon substituents are alkyl groups containing 12 to 18 carbonatoms form especially effective quaternary ammonium salts for thepurposes of this invention. The two long-chain aliphatic hydrocarbonN-substituents can be derived from natural fats and oils, for example,coconut oil, soybean oil, animal tallow and the like. In such instancesthe long-chain aliphatic hydrocarbon radicals will consist essentiallyof mixed alkyl and alkenyl groups containing 8 to 22 carbon atoms. Thetwo short-chain aliphatic hydrocarbon N-substituents can be any loweralkyl group, although methyl and ethyl substituents are preferred forthe reason that they tend to minimize hindrance to addition of thelong-chain substituents to the nitrogen atom. These substituents cancomprise, for example, isopropyl, propyl, or butyl radicals. Examples ofpreferred quaternary ammonium hydroxides are didodecyldimethylammoniumhydroxide, ditetradecyldimethylammonium hydroxide,dihexadecyldimethylammonium hydroxide, and dioctadecyldimethylammoniumhydroxide. Examples of other quaternary ammonium hydroxides that can beused are dioctyldiethylammonium hydroxide, didodecenyldibutylammoniumhydroxide, dioctadecenyldimethylammonium hydroxide anddioctadecadienyldiethylammonium hydroxide.

The nature of the acidic component of the quaternary ammonium saltsdisclosed herein is of great importance to the present invention,inasmuch as the acidic components contribute significantly to theantistalling properties of the quaternary ammonium salts. Nevertheless,various oil-soluble acids of the class disclosed above can be used toform quaternary ammonium salts that are useful for the purposes of thisinvention. Oil-soluble organic monocarboxylic acids that can be used toform salts of this invention will normally contain 7 to 30 carbon atoms.Quaternary ammonium salts wherein the anionic substituent is asalt-forming radical derived from petroleum naphthenic acids constitutea preferred class of carboxylic acid salts. As is known, such naphthenicacids are mixed alicyclic monocarboxylic acids recovered by alkaliwashing of petroleum such as kerosene, naphtha, gas, oil, andlubricating distillates. The acids derived from these distillates aremixtures of alicyclic monocarboxylic acids containing about 7. to 30carbon atoms per molecule, which mixtures have average molecular weightsin the range of about 200 to 450. Within the general class of petroleumnaphthenic acids, the higher molecular weight acids derived from higherboiling distillates and containing 14 to 30 carbon atoms per moleculeand having molecular weights of about 250 to 450 are considered to formespecially effective quaternary ammonium salts for the purposes of thisinvention. Examples of other monocarboxylic acids that can be used toform quaternary ammonium salts whose use is included by this inventionare: oil-soluble synthetic naphthenic acids such as cyclo- .hexylacetic,cyclohexylpropionic, and cyclohexylstearic acids, and oil-solublesaturated or unsaturated fatty acids, such as caprylic, lauric,myristic, palmitic, stearic, oleic, and linoleic acids. Mixtures oflong-chain fatty acids such as those derived from the saponification ofnatural fats and oils also can be used to form quaternary ammonium saltswithin the scope of this invention. Examples of such mixed fatty acidsare coconut, soya, and tallow fatty acids. In such instances the acidswill consist essentially of mixtures of oil-soluble, straight-chain,unsubstituted monocarboxylic acids containing 8 to 22 carbon atoms.

As previously indicated, phenols that form salts whose use is includedby this invention are oil-soluble monohydric phenols having attached tothe aromatic nucleus at least one hydrocarbon substituent containing atleast four carbon atoms and having not more than one substituent in theortho position that contains more than one carbon atom. Althoughmono-substituted phenols are preferred, phenols containing 2 or 3nuclear hydrocarbon substituents can be used. The hydrocarbonsubstituent or substituents can be straight or branched chain andsaturated or unsaturated. The hydrocarbon substituent or substituentsand even the aromatic nucleus itself may contain substituents containinghalogen, oxygen, phosphorous, nitrogen or sulfur, e.g., chloro, nitro,amino, aryl, keto, or mercapto groups which do not affect theoil-solubility of the phenol and which do not react preferentially withthe quaternary ammonium hydroxide. Phenols of the preferred classpossess particularly advantageous solubilizing and salt-formingcharacteristics.

Oil-soluble, monohydric phenols containing one aliphatic hydrocarbonsubstituent, having 4 to 15 carbon atoms, in the meta or para positionto the hydroxyl group are considered to form especially effectivequaternary ammonium salts Within the scope of this invention. Forexample, outstanding results have been obtained with quaternary ammoniumsalts of p-tert-octylphenol. EX- amples of other phenols that formsuitable quaternary ammonium salts are p-tert-butylphenol,p-tert-amylphenol, p-sec-amylphenol, o-sec-arnylphenol,o-tert-amylphenol, p-nonylphenol, cardanol, which consists essentially(approx. of a mixture of C straight chain meta-substituted phenols withdifferent degrees of unsaturation in the side chains, hydrocarbanol,i.e., m-pentadecylphenol, 2,6 dimethyl 4 tert butylphenol, 2 tert amyl4-methylphenol, 3-methyl-6-tert-butylphenol, 2-methyl-4,6-di-tert-butylphenol, and 2,4-di-tert-butylphenol.

As suggested above, oil-soluble acid esters of o-phosphoric acid thatform salts whose use is included by this invention are those having thegeneral formula:

r ITO-1 :0 (gRII wherein R is an aliphatic hydrocarbon radicalcontaining 8 to 22 carbon atoms and R" is a member selected from theclass consisting of hydrogen and aliphatic hydrocarbon radicalscontaining 2 to 22 carbon atoms. Acid esters of o-phosphoric acid thatform a preferred class of quaternary ammonium salts according to thisinvention are those wherein R is an aliphatic hydrocarbon radicalcontaining 8 to 18, and preferably'8 to 12 carbon atoms and wherein R"is an aliphatic hydrocarbon radical containing 2 to 8 carbon atoms.Specific A, i l e,

examples of acid esters of o-phosp'horic acid capable of jk formingpreferred quaternary ammonium salts according to this invention arediisooctyl acid o-phosphate, isoamyl octyl acid o-phosphate, ethyllauryl acid o-phosphate, and ethyl oleyl acid o-phosphate. =Other acidesters of o-pbosphoric acid that form quaternary ammonium salts suitablefor the purposes of this invention are dilauryl acid o-phosphate,dioleyl acid o-phosphate, dimyristyl acid o-phosphate, dipalmityl acido-phosphate, octyl di-acid o-phosphate, lauryl di-acid o-phosphate, andoleyl di-acid o-phosphate.

The sulfonic acids that form quaternary ammonium salts whose use inincluded by this invention are the oilsoluble hydrocarbon sulfonicacids. Such acids may be represented by the generic formula RSO H, whereR is an organic radical of at least predominantly hydrocarbon characterthat is capable of imparting oil-solubility to the acid. These sulfonicacids may be oil-soluble aliphatic hydrocarbon sulfonic acids, includingnaphthenic hydrocarbon sulfonic acids, representative examples of theformer of which are octyl, nonyl, decyl, undecyl, lauryl, tridecyl andmyristyl sulfonic acids, and of the latter, the octyl-, dodecyl-, anddodecenyl-cyclopentyl and similarly substituted cyclohexyl sulfonicacids. Also satisfactory are the alkaryl sulfonic acids such as octyl,decyl, dodecyl and cetyl benzenesulfonic acids, as well as the socalledkeryl, or kerosene, and wax-alkyl benzenesulfonic acids, including thecorresponding dialkyl benzenesulfonic acids. The preferentiallyoil-soluble petroleum sulfonic acids, normally referred to as mahoganyacids, in order to differentiate them from the preferentiallywater-soluble green acids, are especially suitable for the purposes ofthis invention. As is well known in the art, oil-soluble petroleumsulfonic acids can be derived by sulfonation of higher boiling petroleumfractions, normally those having lubricating properties, withconventional sulfonating agents such as oleum, sulfur trioxide, or thelike. able from the thus-treated oils by neutralization With aqueousalkali, such as aqueous caustic soda solution, extraction with alcoholor aqueous alcohol, distillation to remove the extraction solvent, andregeneration of the sulfonic acid by treatment of the residue with anequivalent amount of a mineral acid. Particularly suitable mahoganyacids are those having an average molecular Weight between about 400 andabout 650.

The antistalling addition agents disclosed herein are useful whenincorporated in gasoline compositions of the type disclosed in anyamount sufficient to reduce the engine stalling characteristics thereof.For example, an improvement in the stalling characteristics of gasolinesof the type disclosed herein will normally be obtained by additionthereto of the herein disclosed addition agents in amounts of at least0.001 percent by weight of the composition (approx. 2.5 to 2.6 lbs./1000 bbls. gasoline). Preferably the anti-stalling addition agentsdisclosed here in will be employed in proportions of at least 0.006percent by weight of the composition (approx. lbs./ 1000 bbls.gasoline). Thus, a marked improvement in the stalling characteristics ofgasolines has been obtained by incorporation therein of addition agentsof the kind disclosed herein in proportions of about 15 to 25 pounds perthousand barrels of gasoline. Accordingly, We normally prefer to employthe addition agents disclosed herein in proportions of about 15 to 50pounds per thousand barrels of gasoline. Although in some instances itmay be desired to employ the antistalling addition agents disclosedherein in amounts in excess of 250 pounds per thousand barrels ofgasoline, that is, 0.1 percent by weight or more, such proportions areusually not necessary and normally produce no significant additionalimprovement in the stalling characteristics of the gasoline. In noinstance should the antistalling addition agents disclosed herein beadded to gasoline in amounts such as to produce a significant adverseeffect on the volatility, combustibility, antiknock or gum-forming char-I l acteristics of the gasoline.

It will be appreciated that the optimum proportion of the antistallingaddition agents disclosed herein can vary within the range indicatedabove in accordance with the particular gasoline employed, inasmuch asthe problem of engine stalling due to carburetor icing is a function ofthe 50 percent ASTM distillation point of the gaso- The oil-solublesulfonic acids are recover- 6 line. Thus, greater concentrations of theantistalling addition agents are normally desirable with decreasing 50percent ASTM distillation points. The optimum concentration of theantistalling addition agents disclosed herein may also vary somewhat inaccordance with the particular make and model of engine in which thegasoline is used, as well as in accordance with the severity of theatmospheric conditions encountered. With regard to this last-mentionedfactor, the problem of engine stalling due to carburetor icing resultingfrom the refrigerating effect of evaporating gasoline upon moisturecondensed from the atmosphere has been found to be serious at lowtemperatures, e.g., 35, 40, 45, 50, and when the relative humidity is inexcess of about 55 percent, e.g., 75 percent, and 99 percent. Theoptimum proportion of the antistalling addition agents disclosed herein,in any given case, will be sufficient to effect substantial reduction inthe stalling tendencies of the fuel at the particular atmosphericconditions of temperature and humidity which are likely to beencountered in service.

Practically speaking, the problem of engine stalling due to carburetoricing caused by rapid evaporation of gasoline occurs only in connectionwith gasolines having a 50 percent ASTM distillation point less than 235F. While occasional engine stalling may occur as a result of carburetoricing at severe atmospheric conditions of temperature and humidity withgasolines having somewhat higher 50 percent ASTM distillation points,experience has indicated that the problem does not assume majorimportance except with gasolines of the character indicated. Asindicated, the problem of engine stalling due to carburetor icing isespecially severe in connection with gasolines having a 50 percent ASTMdistillation point of less than about 220 F. The invention is importantin connection with such gasolines. The term gasoline is used herein inits conventional sense to include hydrocarbon mixtures having a percentASTM distillation point of not more than about 392 F. and a 10 percentASTM distillation point of not greater than 149 F. However, it isobvious that some deviation from these limits can be tolerated withoutsubstantially changing the essential characteristics of a gasoline.Accordingly, the invention includes the use of borderline gasolines ofthis kind.

The antistalling addition agents whose use is included by this inventioncan be incorporated in the base gaso line fuel compositions in anysuitable manner. Thus, they can be added as such to gasoline or in theform of dispersions or solutions in solvents such as butanol,isopropanol, ethanol, methanol, benzene, toluene, heptane, kerosene,gasoline, mineral lubricating oil, or the like, which solvents may be ormay not themselves contribute to the antistalling characteristics of thegasoline motor fuel composition. If desired, the herein disclosedantistalling addition agents can be incorporated in gasoline fuelcompositions in admixture with other materials designed to improve oneor more properties of the gasoline, such as antioxidants, anti-gummingagents, e.g., 2,6- ditertiarybutyl, 4-methylphenol, antiknock agents,e.g., tetraethyl lead, lead scavenging agents, e.g., ethylene dibromide,ethylene dichloride, corrosion inhibitors, e.g., oil-soluble dialkylamine phosphates, dyes, and the like.

The utility of the gasoline motor fuel compositions of this inventionhas been demonstrated by two diiferent test procedures. In one test,referred to hereinafter as the Mock Fuel System Test, test fuel issupplied at about 50 F. together with air at about 60 F. and about 75percent relative humidity at controlled rates to the glass vaporizerchamber held at an absolute pressure of 12 inches of mercury(temperature initially at 50 F.), and by observing the time for icing tooccur on a movable brass throttle plate positioned in the vaporizerchamber. Performance of a test fuel is determined by comparing the timefor icing formation on the brass throttle plate with that required forthe uninhibited fuel under the same test conditions. In these tests thebase gasoline employed,

7 hereinafter referred to as Test Fuel A, had the followingcharacteristics.

isooctyl o-phosphoric acids, hereinafter referred to as Compound 3.Bis(dioctadecyldimethylammonium) iso- Ins ectiorw octyl o-phosphate anddioetadecyldimethylammonium dip g, API 62 6 isooctyl o-phosphate werethe predominant components Knock Rating of Compound 3. The mixed acidesters of o-ph ph ric Motor m'ethod octane No 842 acid employed inpreparing Compound 3 comprised a Research method octane I mixture ofdiisooctyl acid 0-ph0sphate and i YI TEL ml /ga1 u 3 acid o-phosphate inapproximately 1:1 mol proportion vapljr g'fi 'ig 4 This mixture of acidshad an average molecular W igh Distillation gagolinez 10 of about 266, aphosphorus content calculated as P2 5 of Over imint e F 100 27.0percent, a specific gravity at 25 C./4 C- Of 1.020, End point e 394 arefractive index at 25 C. of 1.4428. Another quater- 10% evapgrated at oF 135 nary ammonium salt tested was the di(hydrogenated al- 50%evaporated at o F 210 low alkyl)dimethylarnmoniurn salt of oil-solublepetro- 90% fivaporated at F 316 leurn sulfonic acids, hereinafterreferred to as Compound 4. An oil solution of the oil-soluble petroleumsulfonic According to the other test procedure employed, hereacidsemployed in the separation of Compound 4 had an inafter referred to asthe Cold Room Engine Test, a 216 ash content of 0.25 percent and aneutralization number cu. in. Chevrolet engine employing a standardCarter of 35.2. The petroleum sulfonic acids component of the down-draftcarburetor, is Operated at no load 0 a st solution had a calculatedaverage molecular Weight of stand under cycling conditions in a coldroom maintained about 460. at -F. for a warm-up period of 20 cycles.Each cycle The results of the above-described tests are set forthcomprises 40 seconds at 2000 rpm. followed by an idle in the followingtable:

Table A Test Test Example Fuel 1 2 Fuel 3 4 5 6 A B Make-Up, Percent byVol.2

Test Fuel A To B Added Lb./l 000 Bbls Compound Compound2 Compound 3Compound 4 Inspections:

Mock Fuel System Test Time to Icing, Min Cold Room Engine Test StallsEncountered During Warm-Up, No

for 20 seconds at 450 r.p.rn. Air is supplied to the carburetor atambient conditions and at approximately 85 percent relative humidity.The number of engine stalls is observed and reported as stalls per 20cycles. The base gasoline employed in connection with this testprocedure, hereinafter referred to as Test Fuel B, had the followingcharacteristics.

One of the compounds employed in the abovedescribed tests Wasdi(hydrogenated tallow alkyl)dimethylammonium naphthenate, hereinafterreferred to as Compound 1. This salt was prepared from petroleumnaphthenic acids boiling in the range 145 to 185 C. at 3 mm. Hg, havinga neutralization value of 213 and an average molecular Weight of about38 The hydrogenated tallow alkyl radical consists essentially of amixture of (1 E1 and C13H37 radicals, with the latter predominating.Another salt employed in the tests was di(hydrogenated tallowaIkyDdimethylammonium p-tert-octyl phenate, hereinafter referred to asCompound 2. Another material tested was a mixture of neutraldi(hydrogenated tallow alkyl) dirnethylammonium salts of a mixture ofisooctyl and di- From the experimental results presented in theforegoing table it will be seen that the quaternary ammonium salts ofthe class disclosed herein are effective in reducing the carburetoricing tendencies of gasolines that normally tend to promote carburetoricing. The results obtained indicate that Compounds 2 and 3 areespecially effective gasoline antistalling agents.

It will be understood that the invention is not limited to the specificcompositions disclosed above and that good results can be obtained bythe substitution of other normally stalling gasolines and by thesubstitution of other quaternary ammonium salts disclosed herein in thesame or equivalent proportions for the corresponding components therein."For example good results can be obtained by incorporating into TestFuel A and Test Fuel B in the proportions of 25 pounds per thousandbarrels of gasoline of the dioctyldimethylammonium, thedidodecyldiethylammonium, the dihexadecyldipropylammonium, and thedioctadecenyldimethylammonium salts of petroleum naphthenic, oleic,stearic, caprylic, and cyclohexylstearic acids, p-tert-amylphenol,p-sec-amylphenol, o-sec-amylphenol, o-tert-amylphenol, p-nonylphenol,cardanol, m-pentadecylphenol, 2,6-dimethyl-4-tert-butylphenol, 2-tert-amyl-4-methyl-phenol, 3-methyl-6-tert-butylphenolZ-methyl-4,6-di-tert-butylphenol, 2,4-di-tert-butylphenol, diisooctylo-phosphoric acid, is'ooctyl o-phosphoric acid, dilauryl o-phosphoricacid, dirnyristyl o-phosphoric acid, dioleyl o-phosphoric acid, octylo-phosphoric acid and ethyl lauryl o-phosphoric acid.

It is emphasized that the remarkable properties of the addition agentsdisclosed herein are attributable both to the nature of the covalentN-substituents and of the ionic N-substituent. Indicative of theimportance of the character of the covalent N-substituents of thequaternary ammonium salts Whose-use is included by this invention is thefact that benzyltrimethylammonium p-tert-octyl phenate and thetetramethyl ammonium salt of oil-soluble petroleum sulfonic acids werefound to be substantially insoluble in benzene, even in lowconcentrations, thus in dicating the unsuitability of these materials asgasoline additives. Indicative of the importance of the character of theionic N-substituent is the fact that dihydrogenated tallowdimethylammonium chloride, even in the proportion of 250 pounds perthousand barrels of gasoline, was found to extend the time for icing inthe Mock Fuel System Test to only three minutes, an unsatisfactoryperformance according to the test.

To the gasoline fuel compositions of the present invention there can beadded one or more additional agents designed to improve one or morecharacteristics of the gasoline fuel. For example, antioxidants,antiknock agents, ignition control additives, other de-icing agents,antirust agents, dyes, lead scavenging agents and the like can be addedto the gasoline compositions of this invention and the inventionspecifically includes gasoline compositions containing such additives.

Numerous additional embodiments of the invention will readily suggestthemselves to those skilled in the art. Accordingly, only suchlimitations should be imposed on the invention as are indicated in theclaims appended hereto.

We claim:

1. A gasoline motor fuel composition comprising a major amount of ahydrocarbon mixture boiling in the gasoline range, that has a 50 percentASTM distillation point not greater than 220 F. and that normally tendsto promote stalling of internal combustion engines and a minor amount,sufficient to reduce the engine stalling characteristics of saidcomposition of a quaternary ammonium salt wherein two of the co-valentN-bonds are attached to aliphatic hydrocarbon substituents containing 8to 22 carbon atoms and the remaining co-valent N- bonds are attached tosaturated aliphatic hydrocarbon radicals containing 1 to 4 carbon atoms,and wherein the ionic N-bond is attached to an anionic salt formingradical derived from a member selected from the group consisting of (a)oil-soluble organic monocarboxylic acids containing 7 to 30 carbon atomsper molecule, (b) oilsoluble monohydric phenols having attached to thearomatic nucleus one to three hydrocarbon substituents containing atleast four carbon atoms, and having not more than one substituent in theortho position that contains more than one carbon atom, (c) oil-solublemonoand di-acid esters of o-phosphoric acid having as one phosphatesubstituent an aliphatic hydrocarbon radical containing 8 to 22 carbonatoms, and as another a member selected from the class consisting ofhydrogen and aliphatic hydrocarbon radicals containing 2 to 22 carbonatoms, and (d) oil-soluble hydrocarbon sulfonic acids.

2. The fuel composition of claim 1 where said minor amount is 0.001 to0.1 percent by weight of the composition.

3. The fuel composition of claim 1 where said minor amount is about 15to pounds of said quaternary ammonium salt per thousand barrels of saidhydrocarbon mixture.

4. The fuel composition of claim lwhere said quaternary ammonium salt isthe di(hydrogenated tallow alkyl) dimethylammonium salt of petroleumnaphthenic acids.

5. The fuel composition of claim 1 where said quaternary ammonium saltis di(hydrogenated tallow alkyl)dimethylammonium p-tert-octyl phenate.

6. The fuel composition of claim 1 where said quaternary ammonium saltis di(hydrogenated tallow alkyl)dimethylammonium diisooctyl o-phosphate.

7. The fuel composition of claim 1 where said quaternary ammonium saltis his [di(hydrogenated tallow alkyl)] dimethylammonium isooctylo-phosphate.

8. The fuel composition of claim 1 where the quaternary ammonium salt isa mixture of neutral di(hydrogenated tallow alkyl)dimethylammonium saltsof isooctyl and diisooctyl o-phosphoric acids.

9. The fuel composition of claim 1 Where said quaternary ammonium saltis the di(hydrogenated tallow alkyl) dimethylammonium salt ofoil-soluble petroleum sulfonic acids.

References Cited in the file of this patent UNITED STATES PATENTS2,550,982 Eberz May 1, 1951 2,563,506 Werntz Aug. 7, 1951 2,582,733Zimmer et al. Jan. 15, 1952 2,632,694 Watkins Mar. 24, 1953 2,706,677Duncan et al. Apr. 19, 1955 2,819,954 Gebelein et al Jan. 14, 19582,843,464 Gaston et al. July 15, 1958 2,862,800 Cantrell et al. Dec. 2,1958 2,863,742 Cantrell et al. Dec. 9, 1958 2,905,541 Gottshall et a1Sept. 22, 1959 FOREIGN PATENTS 35 6,717 Great Britain Sept. 7, 1941791,394 Great Britain Mar. 5, 1958 OTHER REFERENCES Petroleum RefiningWith Chemicals, by Kalichevsky et al., 1956, Elsevier Pub. 00., p. 480.

1. A GASOLINE MOTOR FUEL COMPOSITION COMPRISING A MAJOR AMOUNT OF AHYDROCARBON MIXTURE BOILING IN THE GASOLINE RANGE, THAT HAS A 50 PERCENTASTM DISTILLATION POINT NOT GREATER THAN 220*F. AND THAT NORMALLY TENDSTO PROMOTE STALLING OF INTERNAL COMBUSTION ENGINES AND A MINOR AMOUNT,SUFFICIENT TO REDUCE THE ENGINE STALLING CHARACTERISTICS OF SAIDCOMPOSITION OF A QUATERNARY AMMONIUM SALT WHEREIN TWO OF THE CO-VALENTN-BONDS ARE ATTACHED TO ALIPHATIC HYDROCARBON SUBSTITUENTS CONTAINING 8TO 22 CARBON ATOMS AND THE REMAINING CO-VALENT NBONDS ARE ATTACHED TOSATURATED ALIPHATIC HYDROCARBON RADICALS CONTAINING 1 TO 4 CARBON ATOMS,AND WHEREIN THE IONIC N-BOND IS ATTACHED TO AN ANIONIC SALT FORMINGRADICAL DERIVED FROM A MEMBER SELECTED FROM THE GROUP CONSISTING OF (A)OIL-SOLUBLE ORGANIC MONOCARBOXYLIC ACIDS CONTAINING 7 TO 30 CARBON ATOMSPER MOLECULE, (B) OILSOLUBLE MONOHYDRIC PHENOLS HAVING ATTACHED TO THEAROMATIC NUCLEUS ONE TO THREE HYDROCARBON SUBSTITUENTS CONTAINING ATLEAST FOUR CARBON ATOMS, AND HAVING NOT MORE THAN ONE SUBSTITUENT IN THEORTHO POSITION THAT CONTAINS MORE THAN ONE CARBON ATOM, (C) OIL-SOLUBLEMONO- AND DI-ACID ESTERS OF O-PHOSPHORIC ACID HAVING AS ONE PHOSPHATOSUBSTITUENT AN ALIPHATIC HYDROCARBON RADICAL CONTAINING 8 TO 22 CARBONATOMS, AND AS ANOTHER A MEMBER SELECTED FROM THE CLASS CONSISTING OFHYDROGEN AND ALIPHATIC HYDROCARBON RADICALS CONTAINING 2 TO 22 CARBONATOMS, AND (D) OIL-SOLUBLE HYDROCARBON SULFONIC ACIDS.